Method of making a pivoted tool having integral pivot member

ABSTRACT

The present invention relates to a method of producing pivoted tools such as scissors, pliers, pruners, and the like. More particularly, this invention is concerned with the method of producing tools having a force applying end with formed handles, and opposed working ends disposed across a pivotable joint. In these tools, the pivotable joint comprises a pivot member formed concurrently with the handles as an integral part of one of the handles.

This is a divisional application of U.S. application Ser. No. 08/023,811filed on Feb. 26, 1993, now U.S. Pat. No. 5,323,592 which is acontinuation-in-part application of U.S. application Ser. No.07/986,057, filed on Nov. 30, 1992, now U.S. Pat. No. 5,341,573.

FIELD OF THE INVENTION

The present invention relates, generally, to pivoted tools such asscissors, pliers, shears, pruners and the like. More particularly, thisinvention is concerned with tools having a force-applying end withformed handles, and opposed working ends disposed across a pivotablejoint, through which a force may be transmitted to the working surfacesof the working ends. In these tools, the pivotable joint, which isformed concurrently with the handles, is an integral part of one of thehandles. Although it will become apparent from the following descriptionthat certain features of the present invention may be utilized inpivoted tools of various construction for application to specific uses,for ease of understanding and convenience, the following descriptionwill from time to time specifically refer to a pair of scissors as themost preferred implementation of the present invention.

BACKGROUND OF THE INVENTION

Pivoted implements having elongated members disposed for cooperativeengagement about a pivotable joint are widely used by those desiring totransmit a force through the pivotable joint to a working piece engagedby the working surfaces of the implement. In particular, pivoted toolssuch as scissors generally comprise two elongated members, typicallymade of stamped or forged metal or other suitable material, disposed forcooperative engagement about a pivotable joint. To facilitate operationof the implement by the user, handles conforming to the fingers or handsof the user are preferably molded onto the force applying end of eachelongated member, or in the case of anvil-type implements, the entireelongated member is typically made of molded material.

Conventional molding operations used to form the handles onto the forceapplying ends consist of positioning one elongated member in a suitablespace in a die casting mold wherein the member is fixed in position withrespect to the mold. A pin or the like going through the pivot pointaperture in the member secures the member with respect to the mold. Asdescribed in U.S. Pat. No. 4,715,122 to one of the present inventors,the space receiving the elongated member communicates with a mold cavityfor the handle portion. The cavity is subsequently filled with a fluidplastic material or the like, whereby the plastic material partiallysurrounds the force applying end (also called tang portion) of theelongated member so that the handle is molded onto the tang. The sameoperation is separately repeated to form the handle on the otherelongated member. The final step in the manufacturing of scissors orother pivotable tools as described above, whether elongated members ofsuch items have earlier been provided with molded handles, consists ofbringing the apertures of the two elongated members into registrationand installing the pivot member to maintain the elongated members incooperative assembled relationship about the pivotable joint.

On the other hand, die cast articulated tools produced by theintercasting technique, such as for example those manufactured inaccordance with the process disclosed in U.S. Pat. No. 4,007,524 toHannes et al., require several casting and adjusting operations. Inparticular, although the intercasting method eliminates the need tolater insert a separate pivot member and screw, in such tools a pivotpin which is integrally formed with a first cast elongated member servesas a mold for the subsequent casting of the other member and pivotconnection. Accordingly, more than one casting operation is required. Asalso disclosed in Hannes, the second casting operation is preferablyfollowed by an appropriate adjustment of the pivot to reduce binding.

From the foregoing, it can be readily recognized that prior art methodsused to manufacture pivoted tools having elongated members, such asscissors or the like, have certain disadvantages. These prior artmethods typically require assembling two members which have previouslybeen separately manufactured, or sequentially casting two members ofdifferent configuration, thereby increasing material handlingrequirements which generally translate into higher unit cost. Thus, itappears desirable to provide pivoted tools such as scissors or the likewhich can alleviate the problems associated with conventionalmanufacturing methods, i.e., which are engineered to lend themselves tofunctional assembling during, as opposed to subsequent to, themanufacturing process, or which otherwise reduce the number ofoperations required to manufacture these pivoted tools.

SUMMARY OF THE INVENTION

The present invention facilitates the manufacturing of scissors or thelike by facilitating the manufacturing process and eliminatingassembling operations typically required with such pivoted implements,and by improving, or at least maintaining the functional quality of thetool. Pivoted tools such as scissors or the like according to thepresent invention are characterized in that a pair of elongated membersare disposed in cavities of a mold to which an uncured or otherwiseflowable polymer, copolymer or the like is supplied, as by injection, toform handles at the force applying end of the members. As explainedabove, in the case of anvil-type implements, only one elongated member(typically the blade member) is disposed in a cavity of the mold whilethe other member (the anvil member) will be molded in its entirety. Inthe case of scissors or scissors-type implements, the mold cavitiesforming the handles are such that the pivot member is formed integrallywith one of the plastic handles. On the other hand, in anvil tools thepivot member will be formed integrally with one of the elongatedmembers. Accordingly, tools in accordance with the present invention canbe constructed without requiring post-manufacturing assemblingoperations.

According to one embodiment of the present invention, in a pivoted toolhaving a pair of elongated members provided with molded handles andpivot member, the pivot member is molded substantially concurrently withthe handles, integrally with one of them.

According to another embodiment of the present invention, in a toolhaving a pair of elongated members pivotally connected about a pivotablejoint, the elongated members being provided with molded handles, thepivotable joint comprising a fastener and a pivot member which is moldedas an integral part of one of the handles, the fastener and pivot membercooperating to permit functional clearance adjustment.

According to a preferred embodiment of the present invention, in a pairof scissors having molded handles and a pivotable joint, the pivotablejoint comprising a fastener and a pivot member molded as an integralpart of one of the handles and formed around the stem of the fastener,the pivot member and fastener cooperating to permit functional clearanceadjustment.

The invention is also concerned with a method for the manufacture ofscissors or the like comprising a pair of elongated members havingmolded handles disposed at the force applying end thereof, and apivotable joint, the pivotable joint comprising a pivot memberintegrally formed with one of the handles. As a result, manufacturingscissors in accordance with the present invention can be effectuatedmore efficiently and at reduced cost, simplifying the manufacturingprocess and eliminating secondary assembling operations, withoutsacrificing quality.

Other advantages of the present invention will become apparent from thedetailed description given hereinafter. It should be understood,however, that the detailed description and specific embodiments aregiven by way of illustration only since, from this detailed description,various changes and modifications within the spirit and scope of theinvention will also become apparent to those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred exemplary embodiment of the present invention willhereinafter be described in conjunction with the appended drawings,wherein like numerals denote like elements and:

FIG. 1 is a top plan view of a pair of scissors according to the presentinvention;

FIG. 2 is a rear plan view of scissors shown in FIG. 1;

FIG. 3 is a top plan view of a second embodiment of the presentinvention;

FIG. 4 is a fragmentary view of the joint of the scissors shown in FIG.1;

FIG. 5 is a fragmentary view of the joint of the scissors shown in FIG.3;

FIG. 6 is a top plan view of one-half of a mold for the manufacture ofscissors shown in FIG. 1; and

FIG. 7 is a top plan view of the other half of the mold shown in FIG. 6with the blades of the scissors shown in the mold in shadow lines.

DETAILED DESCRIPTION OF A PREFERRED EXEMPLARY EMBODIMENT

The present invention relates to pivoted tools having elongated membersdisposed for cooperative engagement about a pivotable joint wherein aforce, which is applied to the force applying end of the pivoted tool,is transmitted through the pivotable joint to the opposed working end ofthe elongated members and transferred to a working piece engaging suchworking ends. Accordingly, the term "scissors" as used herein from timeto time should also be understood to connote other types of pivotedtools such as pliers, shears, nippers, pruners, etc., while the use ofthe term "plastic" handles and "plastic" pivot member furthercomprehends similar materials including, for example, ceramic or othersuitable material which can be utilized to form the molded handles andpivot. In this vein, those skilled in the art will further appreciatethat the device described herein and its principle of operation, as wellas the method described herein for manufacturing such items and itsprinciples of implementation, are broadly applicable to a wide varietyof pivoted implements generally, and may be adapted to tools other thanscissors. Thus, while the present invention is hereinafter describedwith particular reference to a pair of scissors, the skilled artisanwill note its many other applications.

Referring to FIGS. 1, 2, and 4, a pair of scissors in accordance with afirst embodiment of the present invention, designated generally as 10,is shown to include first and second elongated members 12 and 14.Elongated members 12 and 14 respectively comprise a working end (ascissor blade) 16, 18 which is made of metal, a ceramic material or thelike, and a force applying end 20, 22. Elongated members 12, 14, havingrespective apertures 17, 19, are disposed for cooperative engagementabout a pivotable joint generally designated as 24 with apertures 17, 19in substantial registration.

Referring more particularly to FIG. 4, it is readily apparent thatpivotable joint 24 is integrally formed as part of handle 32 which ismolded on tang 28 of force applying end 22. Handle 32 terminates atpivotable joint 24 by a tongue 36, molded integrally with handle 32, andlying adjacent and effectively in contact with the outer surface 38 ofworking end 18. Pivotable joint 24 comprises a shank 40, projecting fromtongue 36 through registering apertures 19 and 17 into engagement withinterior surfaces 42 and 44 of apertures 17, 19, respectively. Shank 40,which extends through aperture 17 beyond the outer surface 46 of workingend 16, terminates by a head 48, lying adjacent and effectively incontact with outer surface 46. To maintain elongated members 12, 14pivotally assembled, head 48 has a diameter which is larger thataperture 17.

It should be recognized that in the case of anvil-type implements,typically, elongated member 14 will be formed as one single element(i.e., combining force applying end 22 and working end 18 into onemember). In that case, pivoted tool 10 would not include aperture 19 asworking end 18 would not be assembled to force applying end 22 butrather would be formed integrally therewith.

As it is well known in the scissor manufacturing art, scissors typicallyrequire a certain amount of camber between the inner surfaces of theblades. Accordingly, to provide functional adjustment of the amount offriction desired between the inner surfaces of these blades, a fastenermay be used to adjust the compressive force applied to the pivotablejoint. In that case, and as more particularly shown in the secondembodiment of the invention disclosed in FIGS. 3 and 5, shank 40,extending from tongue 36 through apertures 19 and 17, terminates at apoint lying on or below the junction of aperture 17 and outer surface46. Shank 40 is provided with a threaded bore 50 receiving a threadedfastener 52 used to control the compressive force applied to pivotablejoint 24, thereby allowing adjustment of the amount of friction betweenengaging inner surfaces 54 and 56 of working ends 16 and 18,respectively. It should be noted that this frictional adjustment may beprovided by other means known to those skilled in the art, or may becreated during the manufacturing of tool 10 as will be explained belowas part of the description of a method which may be used to form tool10. It should be recognized as well that shank 40 and tongue 36 couldreadily be adapted to accommodate such other adjustment means withoutdeparting from the scope of the present invention.

As disclosed in FIGS. 4-6, pivotable joint 24 is formed in situ within amold cavity receiving elongated members 12 and 14. Accordingly, shank 40rigorously conforms with apertures 17 and 19. Head 48 (or fastener 52,as applicable) cooperates with tongue 36 to maintain elongated members12, 14, in cooperative assembled relationship about pivotable joint 24.

Referring now to FIG. 6, in an embodiment of the present invention, tomold plastic handles 30 and 32 and pivotable joint 24, elongated members12 and 14 are disposed in a cavity of the mold with inner surfaces 54,56 oppositely facing and with tangs 26, 28 abutting against a commonsurface 60 of the mold. To enable functional operation of pivoted tool10, one of the apertures, such as, for example, aperture 17, mustnecessarily be substantially circular.

Referring to FIG. 5, in a preferred embodiment of the present invention,shank 40 preferably terminates substantially at a point lying on thejuncture of aperture 17 and outer surface 46 when fastener 52 isdisposed in the mold used to form shank 40, tongue 36, and handles 30and 32. This advantageously permits surface 58 of fastener 52 lyingadjacent outer surface 46 to serve as an abutment face preventing theliquid plastic injected in the mold to form handle 32 from expandingbeyond the juncture of aperture 17 and outer surface 46, therebydetermining the extremity of shank 40. If desirable, for functionalreasons, to avoid having outer surface 46 engage surface 58 lyingadjacent thereto, a washer of a different material can be interposedbetween such surfaces by disposing such washer in the mold cavity ofpivotable joint 24.

The invention is also directed toward a method for manufacturing toolsdisclosed herein. To manufacture scissors in accordance with the presentinvention, elongated members 12 and 14 are positioned in the mold, andliquid plastic is fed to a mold cavity communicating with apertures 17and 19 and terminating by a space suitable to form head 48. As shown inFIGS. 6 and 7, the cavity forming head 48 communicates with the cavitiesconfigured to form handles 30, 32 which receive tangs 26, 28,respectively. A feeding conduit connects these cavities to a source offluid material such as plastic or the like.

As previously indicated, pivoted tools require an adjustment of theamount of friction between the inner surfaces of the working ends. Suchadjustment which is usually done manually typically as the last step inthe manufacturing process, consists of, as applicable, striking thepivotable joint with a suitable impact tool or of adjusting the fastenerof the pivoted implement. Accordingly, and because to form head 48pressure is necessarily applied to pivotable joint 24 longitudinally anddownwardly in FIG. 4 along the axis of shank 40, the manufacturingprocess of the various embodiments of tool 10 must also includeappropriate steps, such as those identified in the following paragraph,to impart the necessary amount of functional preset clearance to suchtools.

In particular, in the case of the first embodiment of the presentinvention as illustrated in FIGS. 1, 2 and 4, at the end of the coolingtime when the liquid plastic has sufficiently cooled to retain its shapebut before it has solidified, a force may be applied by suitable meansto the tongue side of pivotable joint 24, upwardly in FIG. 4 along thelongitudinal axis of shank 40. As the mold is also constructed to permitlongitudinal displacement of the cavity used to form head 48 in responseto such force, a force sufficient to longitudinally displace pivotablejoint 24 will as a result establish the desired amount of presetclearance between head 48 and outer surface 46. In the case of thepreferred embodiment, the desired amount of functional clearance iscreated by appropriately loosening fastener 52 before removing assembledtool 10 from the mold.

A pivoted tool according to the present invention can therefore bemanufactured with improved facility and eliminating secondary assemblingoperations typically required when handles are separately molded on theelongated members of such tool. Accordingly, the manufacturing cost oftools in accordance with the present invention is noticeably reduced,and consistency of appearance and functional characteristics of suchtools are also favorably affected.

It is understood that the above description is of a preferred exemplaryembodiment of the present invention, and that the invention is notlimited to the specific forms described. For example, tools inaccordance with the present invention may advantageously be constructedso that the pivot member integrally formed with one of the handles couldalso comprise a feature permitting self-compensation of manufacturingvariances, such as that disclosed and claimed in U.S. Pat. No.5,341,573. The combination of such feature with the present inventionwould therefore eliminate manual finishing operations, facilitatemanufacturing, and eliminate post-manufacturing assembling steps. Insuch case, apertures 17 and 19 would be suitably sized to facilitateimplementation of the self-compensating feature described in that U.S.patent.

Moreover, even though one of the embodiments shown in the Figures is thepreferred embodiment, it is to be noted that this invention, which isbased on pivoted tools having a pivotable joint wherein the pivot memberis integrally formed as part of one of the handles, can be carried outin other manners. For example, it is conceivable that the pivotablejoint can be constructed in a manner different from that disclosedherein as a result of another manufacturing operation. Such combinationand other constructions, however, are considered to be within the scopeof this invention. Accordingly, these and other substitutions,modifications, changes and omissions may be made in the design andarrangement of the elements and in the manufacturing steps disclosedherein without departing from the scope of the appended claims.

We claim:
 1. A method for manufacturing a tool having first and secondelongated members operable across a pivotable joint, each member havingoppositely facing inner and outer surfaces; each member comprising aworking end, a force applying end at the distal end thereof, and ahandle molded into engagement with said elongated member at the forceapplying end thereof; said pivotable joint comprising first and secondregistering apertures, one of each formed in a respective one of saidelongated members, a pivot member joined to first of said handles by atongue, said pivot member having a shank projecting from said tongueinto said apertures, said shank terminating in a head lying adjacent andeffectively in contact with the outer surface of said second of saidelongated members, the method comprising the steps of:disposing saidpair of elongated members in a mold having first and second cavitiesadapted to receive said members with the inner surface of one of saidmembers adjacent to the inner surface of the other of said members, saidapertures being in substantial registration with a third cavityconforming with the shape of said head, said third cavity communicatingwith said apertures and with the handle area of said first cavity; andinjecting a molding material into said third cavity and into selectedareas of said first and second cavities to form in a common moldingoperation said pivot member and said handles.
 2. A method formanufacturing a pivoted tool having a pair of elongated members joinedat a pivotable joint as recited in claim 1 further comprising the stepof exerting a force along the longitudinal axis of said pivot member onthe outer surface of said tongue and toward said pivot member whileretracting selected areas of said third cavity to permit longitudinaldisplacement of said pivot member and thereby impart desired clearancebetween said head and said outer surface of said second of said membersfor functional operation of said pivoted tool.
 3. A method formanufacturing a tool having first and second elongated members operableacross a pivotable joint, each member having oppositely facing inner andouter surfaces; each member comprising a working end, a force applyingend at the distal end thereof, and a handle molded into engagement withsaid elongated member at the force applying end thereof; said pivotablejoint comprising first and second registering apertures, one of eachformed in a respective one of said elongated members, a pivot memberjoined to said first of said handles by a tongue, said pivot memberhaving a shank projecting from said tongue into said apertures, saidshank cooperating with a headed fastener having a stem inserted throughsaid apertures, the method comprising the steps of:disposing said pairof elongated members in a mold having first and second cavities adaptedto receive said members with the inner surface of one of said membersadjacent to the inner surface of the other of said members, saidapertures being in substantial registration and communicating with thehandle area of said first cavity; inserting said stem through saidapertures with the head of said fastener lying adjacent and effectivelyin contact with the outer surface of said second of said elongatedmembers; and injecting a molding material into said third cavity andinto selected areas of said first and second cavities to form in acommon molding operation said pivot member and said handles.
 4. A methodfor manufacturing a pivoted tool having a pair of elongated membersjoined at a pivotable joint as recited in claim 3 further comprising thestep of loosening said fastener to impart a preset clearance to saidjoint.
 5. A method for manufacturing a tool having first and secondelongated members operable across a pivotable joint, each member havingoppositely facing inner and outer surfaces; each member comprising aworking end, a force applying end at the distal end thereof, and ahandle molded into engagement with said elongated member at the forceapplying end thereof, the method comprising the steps of:disposing saidpair of elongated members in a mold configured to receive said membersin registered configuration with the inner surface of one of saidmembers adjacent to the inner surface of the other of said members; andmolding said pivotable joint while said elongated members are disposedin said mold in said registered configuration; wherein said pivotablejoint is comprised of:(a) first and second registering apertures, one ofeach formed in a respective one of said elongated members; and (b) apivot member integrally formed with said first handle, said pivot memberhaving a shank projecting from said first handle through said first andsecond apertures into engagement with the interior surfaces thereof;said shank terminating in a head lying adjacent and effectively incontact with the outer surface of said second elongated member.